Question

Find f'(a) f(t)=2t+1/t+3

Answer 1

I'm going to rewrite f(t) to make it a little easier to use the power rule:
$f(t)=2t+t^{-1}+3$

Now just take the derivative using the power rule:
$f'(t)=2-t^{-2}$

Since they ask for f'(a), we need to replace the t's with a's:
$f'(a)=2-a^{-2}$